BS 1868 Cast steel swing check valve which its opening &closing part itself opens by the flow force of medium to prevent the medium from flowing reversal,is called check valve.The check valve belongs to automatic valve.is mainly applied on the pipeline with single direction flow and only allows the medium flow at direction,which avoids the occurrence of accident.
The check valve is divided into lift check valve,swing check valve and butterfly type check valve by the structure.The lift type check valve is divided into vertical and horizontal.the swing check valve is divided into single-disc,double-disc,The butterfly type check valve is straight type.The above few check valves may be divided into screwed connection,flange connection and welding connection by its connection way.